In the past, the conventional method of measuring low velocity air movement, that is movement of less than 100 feet per minute, is to employ a hot wire anemometer. Such a conventional device provides a heated copper wire and means to sense the change due to the cooling effect of air moving across it. In using such a prior art device, the temperature of the heated wire is affected by ambient temperature as well as the air flow across it; and, the hot wire anemometer senses a very small area, a few millimeters across. Thus, in order to determine the air flow in a pipe, or a duct, or any area of significant size, it is necessary to take numerous measurements at various points and, thereafter, to average these readings. The present invention is of a different structure and is intended to overcome the limitations of the prior art hot wire anemometers described above in that it monitors the ambient temperature of the air and corrects for air temperature and samples a relatively large area giving an instantaneous readout of the average air flow.